Successful percutaneous cannulation of foramen ovale obstructed by completely ossified pterygoalar ligament using the Hartel approach: Two case reports

Ossification of the pterygoalar ligament, which lies inferolateral to the exocranial opening of the foramen ovale, is traditionally considered to be a bony bar that could obstruct percutaneous needle access to the foramen ovale using the Hartel approach. We herein present two case reports of successfully penetrating the foramen ovale by a needle across the pterygoalar bar. Lack of knowledge of this type of presentation might lead to a change in the surgical approach. PATIENT CONCERNS: A 27-year-old woman had an 11-year history of facial pain because of a space-occupying lesion in the left cerebellopontine angle. Neither open surgery nor drug therapy resolved her facial pain. Another 67-year-old woman developed episodic facial pain because of herpes zoster infection 20 days earlier, and she could not achieve pain relief from drug therapy. DIAGNOSES: Both patients were diagnosed with secondary trigeminal neuralgia. INTERVENTIONS: The patients underwent radiofrequency thermocoagulation of the semilunar ganglion via the foramen ovale. OUTCOMES: The three-dimensional computed tomography scan showed that the ipsilateral foramen ovale was obstructed by the pterygoalar bar. However, percutaneous needle cannulation of the foramen ovale was successful using the anterior approach. The facial pain was immediately and completely resolved without complications except for facial numbness. LESSONS: During percutaneous radiofrequency thermocoagulation for the treatment of trigeminal neuralgia, the Hartel approach can still be used when the foramen ovale is blocked by a pterygoalar bar. To our knowledge, this is the first report of such a treatment. Moreover, we herein provide specific technical recommendations to assist surgeons who may encounter such cases in the future.